Electric switch



March 3o, 1943.

Gf A. LENNHOLM ELECTRIC SWITCH Filed OCfc. 23, 1940 A TTORNE Y 1NVEA/TOR i g1/@afar E arUI/alz.

Patented Mar. 30,

ELECTRIC swrron` A Gustav A. Lennholm, nes Moines, iowa, assirnnr toSquare D Compan poration of Michigan y, Detroit, Mich., a cor- .Iimputation october z3, 1940, serial No. :02,339

' (o1. zoo-67) I 10, Claims.

'I'hls invention relates to electric switches and more particularly t animproved form of electric switch operating with a snap action.

One object of the present invention is to provide I an improved form ofelectric switch having an economy and simplicity of construction.

Another object of the present invention is to provide an improved formof electric switch having provision for breaking a contact weld andrestoring the switch to. normal operation,

Another object of the present invention is to provide an improved formof electric switch in which the contacts are .so moved as to provide asubstantial wiping action before moving to disengaged position.

Another object of the present invention is t0 provide an improved snapacting electric switch in which a substantial contact pressure ismaintained until the instant/the contacts are quickly snapped todisengaged position.

Other objects and features of this invention will be readily apparent tothose skilled in the art from the following specification and appended.drawing illustrating certain preferred embodi- Figure 4 is a sectionalview on the line IV-IV of Figure 2.

Figure 5 is a sectional view on the line V V of Figure 1.

Figure 6 is a sectional view on the line VI--VI of Figure 2.

The switch of the present invention is adapted for actuation bothmanually, and automatically in response to an external force. Theembodiment as illustrated can be used in connection with a float' forsump operations. Reversing of the switch top for bottom enables its usefor tank operations.

closure I at one end thereof and on these ledges are secured conductingmembers 1 and H by means of studs 8 and I2, the member II being furthersecured to the back Wall lI3 of the en' closure as by a stud I4. StudsI5 and `I6 are threaded into the conducting members 1 and II members land II by an upstanding wall portion- 2l.v A generally U-shaped lever orsupporting member 22 is pivotally mounted upon the supporting member I9,the legs of the lever 22 pivoting within seats provided by the legs 23and 24 of the supporting member I 9. switching member 25 formed of aninsulating plate 26 and a metallic member 2l has an opening 2B thereinthrough which projects a narrowed ex,-

tension 29 of the lever 22 with the shoulder portions 3I on the lever 22affording a support for insulating plat. 26. loosely supported on theplate 26 at .one end thereof and serves to bridge the stationarycontacts I'I and I8 to complete the circuit therethrough. A dependingtongue 33 bent' from the metallic member 21 extends through opening 28.

and provides a point of attachment for one end of an operating spring35. The tongue 3,3 is bent upwardly atits end 36 where the operatingspring is attached and extends through the legs 31'and 38 of the levermember I9 when the contacts are in engaged position. This thus placesthe point -of attachment Aof the end of the spring 35 above the plane ofthe upper face of lever member 22 as viewed in Figure l for a purpose tobe hereinafter described; 'l ie opposite end of the spring 35 is securedto a. generally U-shaped operator 4 I. The

'. operator is pivotally mounted upon the supporting The electricaccording .to the present' y invention, comprises an enclosure I havinga removable iront cover 2, adapted to bev secured thereto. Two winglikeportions 3 and 4 having openings therethrough for the passage of studsare provided upon the enclosure for the ready attachment of the switchat the desired operating point. Ledges 5 and 6 are provided within theenmember I9, with its legs disposed outside the supporting member buthaving projections thereon cooperating with seats provided in the legs42 and 43 of the supporting member. The spring 35 serves to definitelybias both the lever 22 and the operator 4I firmly within theirrespective seats on the supporting member. The extent of pivotalmovement of the operating member 4I is defined by the oppositelydisposed surfaces 45 and 43 on the legs 23 and 25 of the supportingmember. Ari. inwardly directedangell carried by la. leg of A contactcarrying or A movable contact 32 is the operating member 4I is adaptedto positively engage the lever member 22 to initiate the movement of theparts from the engaged to the disengaged position. This flange, throughits ability to positively engage the lever member 22, thereby alsoserves to force the contacts apart to break any weld which might occurbetween the contact surfaces. A terminal junction plate 48 is securedtothe back of the base I3 of the enclosure I by a stud 49 and carriesthe studs 5I and 52 to serve as means for connecting circuit wiresthereto, this junction plate being insulated from the other switchparts.

In the operation of the device from .the "on position shown in Figure 1to the off position shown in Figure 2, the operator 4I moves in aclockwise direction to first bring the flange 41 int?) engagement withthe lever member 22 thereby initiating the movement of the lever member22 and of the switching member 25 carried thereon. Movement;` of theoperator moves the operating spring 35 and this tends to move thecontact carrier generally vertically, as shown,v the lever 22 pivotingabout its mounting or supporting member I9. The movements of both theoperator 4I and the lever 22 continue thus until spring 35 is carriedthrough the pivots of lever 22 whereupon the lever quickly snaps to itsfull open position of Figure 2. The lever 22 is limited in its oppositemovements by the engaging of insulating plate 26 with top and bottomwalls of the enclosure. -It is to be noted that the attaching of the endof operating spring 35 to the portion 35 of the tongue 33 to place thepoint of attachment above the plane of the upper surface of lever member22 and above the horizontal on the stationary contact surfaces whilecontact pressure' is positively maintained. 'I'his movement continueseither through positive engage-- manually or by any exterior means, butthe plane through the point of engagement of carriez-25 and lever member22 when the contacts are engaged will cause the force of the spring $5to act upon the contact carrier 25 to urge it in 4a. clockwiseAdirection about its abutting engagement with the shoulders 3l of thelever member 22. The carrier is prevented from-moving in this directionthrough the engagement of the movable'contact 32 with the stationarycontacts .I'I and I8 so that the force of `thespring 35 urging theclockwise movement of the carrier 2l causes the movable contact 22 topresstightly against the stationary contacts I'I and I8 therebyproviding a. very definite contact pressure. This definite contactpressure is maintained while the contact carrier 25 and the movablecontact 32 are being moved in a generally vertical direction and untilthe spring 35 is carried through the pivot point of the lever 22 tothereby shift the direction of the force of the spring 35 to quicklymove said lever 22, the contact carrier 25 and the movable contact I2thereon in a counterclockwise direction.

In the movement of the operating member 5I from the o to the onposition, spring 55 is carried inthe reverse direction through thepivots of lever 22 whereupon the carrier 25, contact I2 and lever 22will be quickly snapped in clockwise direction to the contacts engagedposition of Figure 1. In this movement, prior to the snapping action,the carrier 25 will rotate counterclockwise about the shoulders 3| sothat proper engagement of contact I2 with the stationary contacts isassured and the possibility of accidental edge contact is prevented. Anadditional feature of the switch is the relatively large wiping actionof the contacts which is secured. In the movement from on" to off, themovable contact will slide for a very appreciable distance switch hasshown itself especially adapted for operation by a float in response tochanges in liquid level, such as used in the control of sump pump motorsand similar liquid level regulators.

While certain preferred embodiments of the invention have beenspecifically disclosed, it is understood that the invention is notlimited thereto and is to be given its broadest possible interpretionwithin the terms of the following claims.

What is claimed is:

1. In an electric switch, a stationary contact.

-switching member, .means operative to displace the point of attachmentof saidovercenter spring to the switching, member from one side to theother of the pivotal Asupporting element to urge a rotative movement ofsaid switching member relative to said pivotal supporting element beforesaid switching Imember and said pivotal 'supporting yelement arefsnapped to a second position.

2. Inlanelectric switch, a stationaryV contact, a movable contact, ayswitching member movable tomove said movable'contact to engaged 'anddisengaged "positions, a fixed supporting `member, a generallyU-shapedmember supporting said switching member and. being pivotallymounted on the fixed supportingmember, an

overcenter spring-means secured to said switching member, meansoperativeito move saidv overcenter spring means to wholly displace theline of action thereof from one side of said U-shaped member to theother side thereof to effect a pivotal movement of said U-shaped memberwhile said U-shaped member is moving between con- .taJcts engaged anddisengaged positions, said means including a pivotally mounted operatinglever having the legs thereof disposed outside oi' said generallyIJ-shaped member.'

3. In an electric switch, a stationary contact, a movable contact, aswitching member movable to move said movable contact into and out ofengagement with said stationary contacts, a ilxed .supporting member, a'movable supporting member for said switching member pivoted on saidfixed supporting member, an overcenter spring means `secured to saidswitching member, said spring means exerting its bias to maintain saidmovable supporting member in position upon said iixed supportingmembenmeans to move said spring means to effect pivotal movement of saidmovable supporting member and a generally rectilinear movement of saidmovable contact face across said stationary contact lface before saidspring means passes through the p ivot of said movable supportingmember, movement of the spring means through said pivot eifecting snapmovement of said movable supporting member and said switchingmember'from an engaged to a disengaged position.

4. In an electric switch, a stationary contact,

`a movable contact, a switching member movable to move said movablecontact into and out of engagement with said stationary contact, a xedsupporting member, a generally .U-shaped member supporting saidswitching member and being pivotally mounted on the xed supporting member, and overcenter spring means secured to said switching member, meansoperable to move said spring means to effect pivotal movement of saidmovable supporting member and a generally rectilinear movementl of themovable contact face across the stationary contact face 'before saidspring means passes through the pivot of the movable supporting member,movement of the spring means through said pivot eecting snap movement ofsaid movable supporting member and said switching member from an engagedto a disengaged position, said means including a pivotally mountedgenerally U-shaped operating member having the legs thereof disposedoutside of said generally U-shaped supporting meml ber, -v

5. In an electric switch, a stationary -contact, a movable contact, aswitching member movable to move said movable contact i-nto engaged anddisengaged positions, a pivotal member support# ing said switchingmember and having. an open-- ingprovided therein, a projection on saidswitching member extending through said opening when the contacts are inengaged positlon'and moving out of saidopeningwhen said movable contactis moved to disengaged position, means to move said pivotal member andto urge rotative movement of said switching member about its supportwhile said pivotal member isin motion to maintain substantial contactpressure between said stationary and movable contacts until the instantof disengagement, said means including an operating member and springmeans interconnecting said operating member and said projection on saidswitching member.

6. In an electric switch, a stationary contact, a movable contact, aswitching member movable to move said movable contact into engaged anddisengaged position, a pivotal member supporting said switching memberand having an opening provided therein, means carried by said lswitching member and oscillatably movable 5 through said opening fromone side to the other of said pivotal member, means operative to movesaid pivotal member and to urge rotative move'- ment of saidswitchingmember about its suppOrt while said pivotal member is moving tomaintain substantial contact pressure between said stationary andmovable contacts until the instant of disengagement, said meansincluding an operating member and springmeans interconnecting saidoperating member and said 'oscillatable' means. Y

'7. -In an electric switch, a stationarycontact, a movable contact, aswitching member carrying said movable contact for cooperation with saidstationary contact, a pivotal Vmember supporting said switching memberand having an opening therethrough, a projection on said switchingmember extending through said opening means to oscillatably move saidprojection through said opening `from one side of said pivotal member tothe other to eiiect iirst a rotative movement of said switching memberabout its engagement with the pivotal member and then to eifect a snapmovement of said switching 5 member and said pivotal member, said meansincluding an overcenter spring secured to said projection and anoperating member for actuating said overcenter spring.

8. In an electric switch, a stationary contact, a

pivotal lever, a contact carrier supported intermediate its ends uponsaid pivotal lever and at substantially right angles thereto, saidcontact carrier having a contact surface disposed thereon adjacent oneend thereof for cooperation with said stationary contactsl to' make andbreak an y electrical circuit therethrough, a projecting memberprovided' on said contact carrier at the opposite end thereof, a pivotaloperating member, a spring interconnecting said operating member andsaid projecting member, an extension on said operating member formovementA thereof, to move the point of attachment of the spring to theprojecting member from one side to the other of the point of support"lof said contact carrier on said pivotal supporting member to move saidpivotal supporting member and to urge rotative movement of said contactcarrier Y about its support while said pivotal member is in I motion tomaintain substantial contact pressure 3'0 between the contactsuntil-said spring means snaps said contact carrier to off position.

9-. Inv an electric switch, a stationary contact, a rst pivotal lever, asecond pivotal lever, each of said pivotal levers being movable from one5 side of the other levers pivot to the other, a contact carriersupported/intermediate its ends upon said iirst pivotal lever, a contactsurface disposed upon said contact carrier adapted to cooperate withsaid stationary contact, a projec- 40 tion' upo'n said contact carrier,and extending from the same side of said contact carrier as said contactsurface is disposed, a spring means interconnecting said projection andsaid second pivotal lever, an extension on said second pivotallever-whereby said lever may be moved to move the line of'force of saidspring means from one side to the other of the plane containing thepivots of said levers to move said projection and actuate said rstpivotal member and urge rotative movement of said switching member aboutits support whilesaid first pivotal member is moving to maintainsubstantial contact pressure between said stationary and movable'contacts until the instant oi' disengagement.

10. In an electric switch, a stationary contact, a support, a pair ofoppositely extending pivotal levers mountedthereon, the pivotal axisforeach lever being located on said support intermediate the ends or theother lever, a contact carrier so having a contact surface thereon forcooperation with said stationary contacts and supported upon one of saidpivotal levers 'atsubstantially right angles thereto, a projectingmember on saidcontact carrier, a spring means interconnecting saidprojecting member and the second of said pivotal levers. an extensiononA said second pivotal lever -for effecting movement thereof to actuatesaid springmeans. to move said projecting portion from one side of'- aplane containing said pivotal axes' to the other to actuate said firstpivotal.

member and to urge rotative 4movement ofsaid switchingmember about itssupportwhile, said pivotal member is inmotion.

Gtrs'rav a'. mNNHoLm

